Using the Power Sensor | Uncertainty of a Measurement |
3-10 Uncertainty of a Measurement
Power measurements have many component parts that affect overall measurement uncertainty when measuring power with the MA24106A sensor:
•Sensor Linearity and Temperature Compensation: Sensor Linearity and Temperature Compensation describe the relative power level response over the dynamic range of the sensor. Temperature Compensation should be considered when operating the sensor at other than room temperature.
•Noise, Zero Set, and Zero Drift: These are factors within the sensor that impact measurement accuracy at the bottom of the power sensor’s dynamic range.
•Mismatch Uncertainty: Mismatch uncertainty is typically the largest component of measurement uncertainty. The error is caused by differing impedances between the power sensor and the device to which the power sensor is connected. Mismatch uncertainty can be calculated as follows:
%Mismatch Uncertainty = 100[1 + Γ1Γ22 – 1]
dB Mismatch Uncertainty = 10log1 + Γ1Γ2where
Γ1 and Γ2 are the reflection coefficients of the power sensor and the device under test
•Sensor Calibration Factor Uncertainty: Sensor Calibration Factor Uncertainty is defined as the accuracy of the sensor calibrated at a standard calibration condition. Anritsu follows the industry standard condition of calibration at a reference power of 0 dBm (1 mW) and an ambient temperature of 25 °C.
MA24106A UG |